Magnet Compound Material Compression Molding
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Solution Overview
Problem
Conventional magnet compound materials used in compression molding struggle to produce elongate magnets with high strength and magnetism while maintaining uniformity and reducing variations, especially when molded into elongate shapes, due to limitations in binder resin particle distribution and magnetic powder orientation, which affects the magnetic flux density and mechanical strength.
Innovation Solution
A magnet compound material with a specific ratio of volume average to number average particle diameter of binder resin particles (1.1 to 1.3), combined with sharp corner-removed magnetic powder grains and a high compounding ratio of magnetic powder, is compression molded in a magnetic field to enhance powder-filling properties and orientation, resulting in high-strength, high-magnetism elongate magnets with reduced variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional ferrite-based magnet is used, then the magnetic flux density can be maintained, but the half-value width cannot be reduced to not more than 20°
Solution Approach 1:
The patent changes the material parameters by transitioning from conventional ferrite-based magnets to rare earth-based magnetic materials (such as Nd-Fe-B or Sm-Co). This material substitution enables achieving both a half-value width of not more than 20° and a magnetic flux density of 100 to 130 mT simultaneously, resolving the contradiction between shape control and magnetic performance.
2Shape
If plastic magnets are produced by injection molding or extrusion molding, then arbitrary shapes can be obtained, but the magnetism is insufficient to reach 13 MGOe
Solution Approach 1:
The patent changes the molding method from injection molding or extrusion molding to compression molding. This parameter change in the manufacturing process enables the production of elongate magnets with high magnetism of 13 MGOe or more while still achieving arbitrary shapes required for the magnet roller, thereby resolving the contradiction between shape flexibility and magnetic performance.
3Quantity of substance
If compression molding is used to produce high-magnetism magnets, then the magnetism reaches 13 MGOe, but the production of elongate magnets with high strength and uniformity is difficult
Solution Approach 1:
The patent applies preliminary action by pre-mixing the magnetic powder and binder resin to create a uniformly distributed magnet compound material before compression molding. This preliminary preparation ensures that when the elongate magnet is compression molded, the magnetic properties and strength are uniformly distributed throughout the structure, achieving both high magnetism (13 MGOe or more) and manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach achieves molded magnets with high magnetic flux density of at least 13 MGOe and reduced variations, enabling the production of high-performance magnet rollers and image-forming apparatus components with improved image quality.
Implementation Method 1
is compression molded in a magnetic field to enhance powder-filling properties and orientation
Data Source
AI summary
A magnet compound material to be compression molded, said magnet compound material comprising a magnetic powder and a binder resin particles, wherein a ratio of Dv to Dn is in a range of 1.1 to 1.3, Dv and Dn of the binder resin particles denote the volume average particle diameter and the number average particle diameter, respectively.